JP2006174422A - Communication apparatus and fault notification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To construct a ring wiring scheme using Ethernet(R) while suppressing increase of costs of an entire communication network. <P>SOLUTION: A switch unit 10 including an STP function is formed on the same semiconductor chip 100 together with a function processing unit 20 including an existent information collection function or control function and connected with the function processing unit 20 and according to the STP, data communication between the function processing unit 20 and another apparatus is controlled via a field bus 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication device, and more particularly to a communication device connected to another communication device via Ethernet (registered trademark).

  In a supervisory control system that monitors and controls building equipment and plant equipment, devices having various functions such as an information collection function and a control function are connected as communication devices via a communication network, and a central monitoring device is based on information from these communication devices. The individual equipment is monitored and controlled. In such a monitoring control system, Ethernet is used as a communication network.

  In the Ethernet, when connecting a plurality of communication devices, a star wiring system is basically used in which each communication device is connected to a hub or a switch. Such a star wiring system is suitable for a relatively small office environment, but is not necessarily suitable for a large-scale facility such as a building facility or a plant facility. The reason is that in the star wiring method, it is necessary to connect each hub and switch to each communication device via individual wiring, which complicates the wiring and increases the burden of wiring work and maintenance. Because it does.

Conventionally, in such Ethernet, an Ethernet switch that connects each communication device by a ring wiring method has been proposed (for example, see Non-patent Document 1).
This Ethernet switch is a relay device that connects a plurality of communication devices in a ring shape via a jumper wiring using an STP (Spanning Tree Protocol) function that realizes redundancy of communication paths. By connecting these Ethernet switches by the ring wiring method and connecting the communication devices to the respective Ethernet switches, a plurality of communication devices can be connected by Ethernet without adopting the star wiring method.

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
http://japan.moxa.com, 2003, Moxa Technologies

However, such a conventional technique has a problem that it is necessary to provide an Ethernet switch for each communication device, which causes a significant cost increase of the entire communication network. In addition, when functions are reduced for cost reduction, there is a problem in that failure occurrence and failure location cannot be accurately identified.
An object of the present invention is to provide a communication device and a failure notification method capable of constructing a ring wiring method using Ethernet while suppressing an increase in the cost of the entire communication network. Yes.

  In order to achieve such an object, a communication device according to the present invention has a function processing unit that realizes a predetermined function by exchanging various data with other devices, and uses an Ethernet-compliant field bus. A switch that is connected to another device by a ring wiring method and controls data communication between the function processing unit and the other device via the field bus based on the spanning tree protocol (STP) And a semiconductor chip on which signal processing circuits constituting the function processing unit and the switch unit are formed as an integrated circuit.

  At this time, as a specific example of the switch unit, two communication ports for controlling termination of fieldbus endpoints connected to each other in the physical layer, and a frame from another device provided for each communication port via the communication port Received by the communication processing port, two queue buffers provided for each communication port for temporarily storing frames received by the reception processing unit, and stored in the other queue buffer for each communication port. A transmission processing unit that transmits a frame to another device via the communication port, and another device that receives the frame addressed to the device stored in the queue buffer to the function processing unit and receives from the function processing unit And a communication control unit that stores the addressed frame in a queue buffer.

  Further, the switch unit is provided with link signal monitoring means for monitoring each link signal on the physical layer periodically exchanged between two adjacent devices adjacent to the communication device via the field bus, When a failure is detected by the link signal monitoring means in the function processing unit according to the abnormality of the link signal from one adjacent device side, a failure detection notification mail including a network address unique to the communication device is generated, There may be provided a mail transmission means for transmitting a failure detection notification mail from the switch unit to an arbitrary mail server by using the field bus on the other adjacent device side where no error is detected.

  Alternatively, a check message for monitoring a check message on the data link layer periodically transmitted to the switch unit so as to circulate on the field bus from the switch device that controls each communication device based on the spanning tree protocol (STP). A monitoring unit is provided, and when a failure is detected in the function processing unit by the check message monitoring unit according to an abnormality of the check message from one adjacent device, a failure detection notification mail including a network address unique to the communication device And a mail transmission means for transmitting a failure detection notification mail from the switch unit to an arbitrary mail server using the field bus on the other adjacent device side on which no failure is detected.

  The failure notification method according to the present invention is a failure notification method used in a communication device connected to another device by a ring wiring method using an Ethernet-compliant field bus, and is formed as an integrated circuit on a semiconductor chip. Integrated into a semiconductor chip and a switch step for controlling data communication between a function processing unit and another device via a fieldbus based on a spanning tree protocol (STP) by a switch unit including a signal processing circuit. And a function processing step for realizing a predetermined function by exchanging various data with other devices via the switch unit by a function processing unit formed of a signal processing circuit formed as a circuit. Is periodically exchanged between two adjacent devices adjacent to the communication device via A link signal monitoring step for monitoring each link signal on the physical layer is provided, and if a failure is detected in the function processing step according to an abnormality of the link signal from one adjacent device side by the link signal monitoring step, the communication Sending a failure detection notification mail including the network address unique to the device, and sending a failure detection notification email from the switch unit to any mail server using the fieldbus on the other neighboring device side where no failure is detected Steps may be provided.

  Further, another failure notification method according to the present invention is a failure notification method used in a communication device connected to another device by a ring wiring method using an Ethernet-compliant field bus, and is provided as an integrated circuit on a semiconductor chip. A switch step for controlling data communication between a function processing unit and another device via a fieldbus based on a spanning tree protocol (STP) by a switch unit including a formed signal processing circuit; and a semiconductor chip A functional processing step that realizes a predetermined function by exchanging various data with other devices via the switch unit by a functional processing unit formed of a signal processing circuit formed as an integrated circuit in the switch step. The switch device that controls each communication device based on the Spanning Tree Protocol (STP) A check message monitoring step for monitoring a check message on the data link layer that is periodically transmitted so as to circulate on the route bus is provided, and a check message from one neighboring device side is abnormal in the function processing step by the check message monitoring step. If a failure is detected according to the communication device, a failure detection notification mail including a network address unique to the communication device is generated, and an arbitrary address is detected from the switch unit using the field bus on the other adjacent device side where the failure is not detected. You may provide the mail transmission step which transmits a failure detection notification mail to a mail server.

According to the present invention, since the switch unit having the STP function and the function processing unit for realizing various functions such as the existing information collecting function and control function are formed on the same semiconductor chip, the STP switch is provided for each communication device. Compared with the case of attaching externally, the cost of members such as the device configuration and connector, and further, the manufacturing cost becomes unnecessary.
Therefore, even in a large-scale monitoring control system that monitors and controls building facilities and plant facilities, it is possible to construct a ring wiring system using Ethernet while suppressing an increase in the cost of the entire communication network.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a communication apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a monitoring control system to which a communication apparatus according to a first embodiment of the present invention is applied.
The monitoring control system is connected to a communication device 1 having various functions such as an information collecting function and a control function via a communication network, and monitors and controls individual facilities by the central monitoring device 4 based on information from these communication devices 1. System.

This monitoring control system is composed of a communication device 1, an STP switch 2, a controller 3, and a central monitoring device 4.
Each communication device 1 includes a switch unit having an STP function, and is connected to the field bus 5 via the switch unit in a ring wiring manner. The field bus 5 is a ring-type communication line compliant with the Ethernet standard, and is connected to the STP switch 2 having the STP function.
The STP switch 2 has a function of terminating one or more field buses 5, a function of connecting to the controller 3 via the communication line 6, and between each communication device 1 and the controller 3 connected to the field bus 5. And has a function of relaying and transferring data.

  The controller 3 has a function of connecting to the central monitoring device 4 via the host network 7, a function of connecting to one or more STP switches 2 via the communication line 6, and an arbitrary communication device 1 via the STP switch 2. Based on the function of acquiring various information collected by the communication device 1 and notifying the central monitoring device 4 by performing data communication, and the instruction from the central monitoring device 4, or a preset control program, It has a function of controlling the operation of the communication apparatus 1 by performing data communication with an arbitrary communication apparatus 1 via the STP switch 2.

  In the present embodiment, the signal processing circuit of the switch unit of each communication device 1 is formed on the same semiconductor chip together with the signal processing circuit of the function processing unit constituting various functions such as an information collecting function and a control function. It is configured to be connected to the field bus 5 via a switch unit by a ring wiring method.

[Communication device]
Next, the communication apparatus according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the switch unit of the communication device according to the first embodiment of the present invention.

  The communication device 1 has a switch unit 10 and a function processing unit 20 as main circuit configurations, and these signal processing circuits are formed on the same semiconductor chip 100 such as an FPGA (Field Programmable Gate Array) as an integrated circuit. Has been. The FPGA is a gate array whose hardware can be dynamically reconfigured (in use) by design data. Since it can be designed by combining small logic modules, it has the advantages of high flexibility and high gate usage efficiency.

The function processing unit 20 includes a CPU, a dedicated arithmetic processing circuit, and the like, and realizes various functions such as an information collecting function and a control function by exchanging various data with other devices.
The switch unit 10 is connected to the function processing unit and is connected to another device via the field bus 5, and the function processing unit 20 via the field bus 5 and other devices are connected based on the Spanning Tree Protocol (STP). It has an STP function for controlling data communication with the apparatus, and is connected to the field bus 5 by a ring wiring system. STP is a layer 2 link management protocol that realizes path redundancy while preventing loops on a network such as Ethernet, and operates on bridges and switches compliant with IEEE802.1d.

  The switch unit 10 is provided with two communication systems A and B for connection to the field bus 5 realizing the ring wiring system. Among these, one communication system A is composed of a communication port A (11A), a reception processing unit A (12A), a queue buffer A (13A), and a transmission processing unit A (14A), and the other communication system B is Communication port B (11B), reception processing unit B (12B), queue buffer B (13B), and transmission processing unit B (14B). The switch unit 10 is provided with a communication control unit 15 that collectively controls the communication systems A and B.

The communication ports A and B have a function of controlling termination of the end points of the field bus 5 connected to each of them in the physical layer.
The reception processing units A and B are provided for each of the communication ports A and B. The communication ports A and B are connected with a media independent MII (Media Independent Interface) interface similar to the physical layer interface of the conventional communication apparatus. And a function of performing reception processing such as preamble discard, CRC check, destination MAC address confirmation on the received data.

The queue buffers A and B are provided for each of the communication ports A and B, and temporarily store frames received by the reception processing units A and B and frames output from the communication control unit 15.
The transmission processing units A and B are provided for each of the communication ports A and B, and have a function of sequentially reading frames from the queue buffers B and A of the opposing communication system, and a communication in which the read frames are IP-connected through the MII interface as transmission frames. It has a function of outputting to ports A and B, and a function of performing transmission processing such as CSMA / CD, preamble reproduction, flow control, etc. for the transmission frame.

  The communication control unit 15 is a circuit unit that performs communication control such as self-node frame transmission / reception, MAC address / table management, failure processing based on STP, and specifically, a function processing unit connected via an MII interface. A function for exchanging frames with the CPU 20 and a frame addressed to the device stored in the queue buffers A and B are output to the function processing unit 20 and a frame addressed to another device received from the function processing unit 20 is output to the queue buffer. A function of storing in A and B and a function of notifying the function processing unit 20 of a request for transmitting an e-mail to the central monitoring device 4 via the interrupt signal line 16 as necessary.

[Communication device operation]
Next, the operation of the communication apparatus according to the first embodiment of the present invention will be described in detail with reference to FIG.
A unique address is assigned to the switch unit 10 on the supervisory control system or the field bus 5, and the store and forward method, half-duplex / full-duplex automatic, by the two-system configuration as described above. A layer 2 switch is configured by recognition or the like. Further, redundancy is realized by using a communication function of STP (Spanning Tree Protocol).

  The communication control unit 15 of the switch unit 10 checks the MAC address of a frame received via the communication ports A and B and stored in the queue buffers A and B, and has a frame having its own node MAC address as a destination address. Are obtained from the queue buffers A and B and output to the function processing unit 20. Frames that do not have their own node MAC address as the destination address are read from the queue buffers A and B, and transferred from the transmission processing units B and A to the fieldbus 5 via the other communication port.

Further, the communication control unit 15 receives the transmission frame from the function processing unit 20 and stores it in the queue buffers A and B, thereby transmitting it to the fieldbus 5.
In addition, the communication control unit 15 performs a line check with another communication device by failure processing, and always checks whether a failure has occurred.

Thus, according to the present embodiment, the switch unit 10 having the STP function is formed on the same semiconductor chip 100 as the function processing unit 20 having the existing information collecting function and control function, and the function processing unit 20 Since the connection is made, compared with the case where an STP switch is externally attached to each communication device, the device cost, the member cost such as the connector, and the manufacturing cost become unnecessary.
Therefore, even for a large-scale monitoring control system that monitors and controls building facilities and plant facilities, it is possible to construct a ring wiring system having redundancy using Ethernet while suppressing an increase in the cost of the entire communication network.

  Further, since the function processing unit 20 is connected to the switch unit 10 through the same MII interface as the conventional physical layer interface of the existing communication device, the existing software can be used on the function processing unit 20 side. The cost increase required for software modification can be suppressed.

[Second Embodiment]
Next, a communication apparatus according to the second embodiment of the present invention will be described with reference to FIG. 1 and FIG. Note that the configuration of the communication apparatus according to the second embodiment of the present invention is the same as that of the first embodiment described above, and a detailed description thereof is omitted here.
In the STP protocol, it is stipulated that one of the communication devices connected by the fieldbus 5 becomes a route (ROOT) to control the protocol. At this time, among the communication devices, the device having the highest protocol priority (priority) set for each communication device becomes the route. If the protocol priority of the communication device connected to the fieldbus 5 later is higher than that of the route up to that point, route change processing occurs and data communication is temporarily suspended.

  In this embodiment, paying attention to the fact that the protocol priority of the commercially available STP switch 2 is set to the medium level, the protocol priority set to the communication control unit 15 of the switch unit 10 is set to the lowest level. Even if the communication device 1 is connected to the fieldbus 5 later, for example, when the communication device 1 is turned on / off, for example, each communication device connected by the ring wiring method is used. In the meantime, the protocol priority for route determination does not change, so that unnecessary route change processing can be avoided, and interruption of data communication due to this can be suppressed.

In FIG. 1, the case where a plurality of ring wiring systems are constructed with the STP switch 2 has been described. However, only one ring wiring system may be constructed with each STP switch 2. Further, as shown in FIG. 3, the controller 3 may be provided with a switch unit similar to that of the communication device 1 to construct a ring wiring system and further to construct an upper network.
In addition, as shown in FIG. 3, a plurality of ring wiring systems can be connected in multiple stages by using the STP switch 2 that can construct a plurality of ring wiring systems as one of the communication devices connected by the fieldbus 5. Even in a large-scale monitoring control system that monitors and controls building facilities and plant facilities, communication devices can be connected efficiently.

[Third Embodiment]
Next, a communication device according to the third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a configuration of a monitoring control system to which the communication apparatus according to the third embodiment of the present invention is applied.
In the present embodiment, in the communication device and the monitoring control system according to the first embodiment described above, each communication device 1 detects an abnormality in the fieldbus 5 that connects each communication device 1 by the ring wiring method. A case where the failure position is notified will be described.

  Compared to the monitoring control system of the first embodiment (see FIG. 1), each communication device 1 (1A to 1N) according to the present embodiment is connected to an adjacent communication device 1 or STP switch 2. Has a function of detecting a failure in the links 5A to 5N, 50, and 51 of the field bus 5 that connects to each other and a failure in each communication device 1.

  Further, as shown in FIG. 4, compared to the monitoring control system of the first embodiment (see FIG. 1), a mail server 8 is newly added to the monitoring control system according to the present embodiment. And is connected to the upper network 7 via the switch 7A. The mail server 8 includes a general mail server that transmits and receives various electronic mails, and sends a failure detection notification mail indicating a communication failure detected by the communication device 1 from the communication device 1 to the STP switch 2, the communication line 6, and the controller 3. The contents of the failure detection notification mail are notified to the central monitoring device 4 according to the access from the central monitoring device 4 and received through the upper network 7 and the switch 7A.

[Communication device]
Next, a communication device according to the third embodiment of the present invention will be described in detail with reference to FIGS. FIG. 5 is a block diagram illustrating a configuration of a switch unit of a communication device according to the third embodiment of the present invention. FIG. 6 is a block diagram showing a detailed configuration of the communication control unit and the function processing unit of the communication apparatus according to the third embodiment of the present invention.

Compared with the communication apparatus according to the first embodiment described above, the communication apparatus 1 (1A to 1N) according to the present embodiment has a function for detecting a failure in data communication via the fieldbus 5. Means are provided.
As shown in FIG. 6, the communication control unit 15 of the switch unit 10 is provided with STP control means 15A, link signal control means 15B, link signal monitoring means 15C, check message detection means 15D, and check message monitoring means 15E. ing. In addition, the function processing unit 20 is provided with mail transmission means 22.

  The STP control means 15A is based on the function of exchanging various data with the queue buffers A and B, the function of exchanging various data with the function processing unit 20 via the data bus 18, and the Spanning Tree Protocol (STP). It has a function of controlling data communication between the function processing unit 20 and other devices via the field bus 5.

  The link signal control means 15B exchanges the link signal A (17A) with the adjacent communication device via the communication port A and the link signal B (17B) with the adjacent communication device via the communication port B. ). Link signals (Link Signaling) A and B are periodically exchanged between adjacent communication devices, for example, at a timing such as a gap between frames on a physical layer used when data communication is performed by Ethernet.

  The link signal monitoring means 15C responds to the function of monitoring the normality based on the period and content of the link signals A and B from the adjacent communication device received by the link signal control means 15B and the abnormality of the link signals A and B. When a failure is detected in data communication with an adjacent communication device, the function has a function of notifying the mail transmission means 22 of the function processing unit 20 of the link where the failure is detected by an interrupt signal 16A.

  The check message detection unit 15D sends the check message from the STP switch 2 stored in the queue buffer A via the communication port A and the reception processing unit A, and the queue buffer B via the communication port B and the reception processing unit B. It has a function of detecting the stored check message from the STP switch 2. The check message is a message on the data link layer that is periodically transmitted from the STP switch 2 to circulate through each communication device 1 on the field bus 5.

  The check message monitoring unit 15E has a function for monitoring the normality based on the period and content of the check message detected by the check message detection unit 15D and a failure in data communication with the adjacent communication device according to the abnormality of the check message. When detected, it has a function of notifying the mail transmission means 22 of the function processing unit 20 of the link where the failure is detected by the interrupt signal 16B.

  The mail transmission means 22 has a function of exchanging various data with the STP control means 15A of the communication control unit 15 via the data bus 18 and the internal bus 21, and an interrupt signal 16A and check message monitoring means from the link signal monitoring means 15C. In response to the interrupt signal 16B from 15E, a function for generating a failure detection notification mail addressed to the mail server 8 including a network address unique to the communication device, and a failure occurrence link notified by the interrupt signals 16A and 16B Has a function of instructing the STP control means 15A to transmit a failure detection notification mail using the opposite side link, that is, the field bus 5 on the adjacent device side where no failure is detected.

  The STP switch 2 performs data communication with each communication device 1 via the field bus 5 based on the Spanning Tree Protocol (STP), and controls these communication devices 1, so that STP control means similar to the communication device 1 is used. In addition to 15A, link signal control means 15B, link signal monitoring means 15C, check message detection means 15D, and check message monitoring means 15E, check message transmission means for periodically transmitting a check message is provided.

[Operation of Third Embodiment]
Next, a link signal monitoring operation of the communication apparatus according to the third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a flowchart showing link signal monitoring processing of the communication apparatus according to the third embodiment of the present invention. FIG. 8 is a sequence diagram illustrating the link signal monitoring operation of the communication device according to the third embodiment of the present invention.

The communication device 1 performs the link signal monitoring process of FIG. 7 by the communication control unit 15 and the function processing unit 20.
First, the communication control unit 15 always exchanges link signals A and B with the adjacent communication device 1 by the link signal control unit 15B, and links from the adjacent communication device 1 by the link signal monitoring unit 15C. The signals A and B are checked for normality based on the detection period and contents (step 100). If there is no abnormality in the link signals A and B (step 101: YES), the process returns to step 100.

On the other hand, for example, when either link signal A or B is not detected in a predetermined cycle due to link disconnection and any of the link signals A and B is abnormal (step 101: YES), the link signal monitoring means 15C The link that detected the failure is notified to the mail transmission means 22 by the interrupt signal 16A.
The mail transmission means 22 confirms the occurrence of a failure based on the interrupt signal 16A from the link signal monitoring means 15C, and generates a failure detection notification mail addressed to the mail server 8 including the network address unique to the communication device (step 102). ). Then, a failure detection notification mail is transmitted to the mail server 8 using the link on the side opposite to the failure occurrence link notified by the interrupt signal 16A, that is, the field bus 5 on the adjacent device side where no failure is detected (step S1). 103) and return to Step 100.

Therefore, as shown in FIG. 8, when link signals are exchanged between the communication devices 1A and 1B via the link 5A (step 110), if the link 5A is disconnected, the communication devices 1A and 1B The link signal monitoring means 15C detects an abnormality in the link signal (steps 111 and 112), generates a failure detection notification mail, and transmits it to the mail server 8 (steps 113 and 114).
These failure detection notification mails include the unique network addresses of the respective communication devices 1A and 1B such as IP addresses. Therefore, by referring to the failure detection notification mail stored in the mail server 8 in the central monitoring device 4 and confirming the network address of the communication device that is the mail transmission source, the location of the failure can be specified.

  As described above, in this embodiment, the link signal on the physical layer that is periodically exchanged between the two adjacent devices adjacent to the communication device 1 via the field bus 5 to the switch unit 10. Link signal monitoring means 15C for monitoring each of them, and in the mail transmission means 22 of the function processing unit 20, when a failure is detected by the link signal monitoring means 15C according to the abnormality of the link signal from one adjacent device side, A failure detection notification mail including a network address unique to the communication device is generated, and a failure detection notification mail is transmitted from the switch unit 10 to the mail server 8 using the field bus 5 on the other adjacent device side where no failure is detected. Therefore, the location of the failure can be specified by checking the network address of the failure detection notification mail.

  Therefore, even when the switch unit 10 having the STP function is formed on the same semiconductor chip 100 as the function processing unit 20 having the existing information collecting function and control function and connected to the function processing unit 20, each communication It is possible to easily detect the occurrence of a failure in each link or each communication device of the fieldbus 5 that connects the devices in a ring connection method, and to easily identify the location of the failure.

  When the link signal monitoring unit 15C of the communication device 1 detects an abnormality in the link signal, the link signal control unit 15B transmits, for example, a link signal to the adjacent communication device 1 facing through the failure link. You may make it notify link signal abnormality using methods, such as a stop. As a result, the link signal abnormality is detected in the adjacent adjacent communication device 1 and the failure detection notification mail is transmitted to the mail server 8, so even if a failure occurs in either the uplink or downlink of the link The failure detection notification mail can be transmitted from both communication devices 1 connected to the link, and the location where the failure has occurred can be specified.

Next, a check message monitoring operation of the communication apparatus according to the third embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a flowchart showing the check message monitoring process of the communication device according to the third embodiment of the present invention. FIG. 10 is a sequence diagram illustrating a check message monitoring operation of the communication device according to the third embodiment of the present invention.

The communication device 1 performs the check message monitoring process of FIG. 10 by the communication control unit 15 and the function processing unit 20.
First, the communication control unit 15 detects whether or not the first check message from the STP switch 2 is received by the STP control unit 15A by the check message detection unit 15D at the time of activation (step 130), and the first check message is received. If this happens (step 131: YES), the check message monitoring means 15E starts a reception timer for a period sufficient to receive the next check message (step 132).

The check message is received by the reception processing unit A via the communication port A and stored in the queue buffer A. Thereafter, the check message stored in the queue buffer A is read by the transmission processing unit B and transferred from the communication port B to the subsequent communication device 1.
On the other hand, the check message stored in the queue buffer A is read and received by the STP control unit 15A of the communication control unit 15, and this is detected by the check message detection unit 15D.

After step 132, the check message monitoring unit 15E detects whether or not the first check message from the STP switch 2 is received by the STP control unit 15A (step 133), and if the check message is not received (step 134: NO), it is determined whether the reception timer has timed out (step 135), and if it has not timed out, the process returns to (step 133).
Here, when the next check message is received before the reception timer times out (step 134: YES), it can be determined that each device and link in the section from the STP switch 2 to the communication device 1 are normal. After stopping the reception timer (step 136), the reception timer is started again (step 137), and the process returns to step 133.

  On the other hand, if the reception timer times out before receiving the next check message (step 135: YES), it can be determined that a failure has occurred in each device and link in the section from the STP switch 2 to the communication device 1. Then, the check message monitoring unit 15E notifies the mail transmission unit 22 of the link where the failure is detected by the interrupt signal 16B.

  The mail transmission means 22 confirms the occurrence of the failure based on the interrupt signal 16B from the check message monitoring means 15E, and generates a failure detection notification mail addressed to the mail server 8 including the network address unique to the communication device (step 138). ). Then, a failure detection notification mail is transmitted to the mail server 8 using the link on the side opposite to the failure occurrence link notified by the interrupt signal 16B, that is, the field bus 5 on the adjacent device side where no failure is detected (step S1). 139), the process returns to step 130.

  Therefore, as shown in FIG. 10, the check message 60 transmitted from the STP switch 2 is sequentially transferred via each link of the fieldbus 5 and the communication device 1, and the blocking set in any of the communication devices 1. It reaches the port (Blocking Port) and is discarded.

  Each communication device 1 starts a reception timer in response to detection of reception of the check message 60 and monitors reception of the next check message. For example, when the check message 60 is received and detected at the time T1A by the communication device 1A, the reception timer TM1A is started at the time T1A. Similarly, the communication devices 1B, 1C,... Start reception timers TM1B, TM1C,... At times T1B, T1C,.

The STP switch 2 transmits a similar check message 61 at time T2 after a predetermined time has elapsed from time T1.
Here, when the link 5A between the communication devices 1A and 1B is disconnected, the check message 61 normally reaches the communication device 1A. Therefore, the communication device 1A performs the next check at time T2A before the reception timer TM1A times out. The message 61 is normally received and detected, and the reception timer TM1A is started again.

On the other hand, since the reception timer TM1B times out at the time T2B before the check message 61 is received and detected, the communication device 1B transmits the failure detection notification mail 70 to the mail server 8. Thereafter, the failure detection notification mail 70 is similarly transmitted from the communication devices 1C to the mail server 8.
These failure detection notification mails include a network address unique to each communication device 1 such as an IP address. Therefore, the central monitoring device 4 refers to the failure detection notification mail stored in the mail server 8 to confirm the network address of the communication device that is the mail transmission source, and sends each failure detection notification email in the transfer order of the check messages. It can be seen that a failure has occurred immediately before the most upstream communication device that has transmitted.

  As described above, in the present embodiment, the switch unit 10 is periodically circulated on the field bus 5 from the STP switch (switch device) 2 that controls each communication device 1 based on the spanning tree protocol (STP). The check message monitoring means 15E for monitoring the check message on the data link layer transmitted to the network is provided, and the mail transmission means 22 of the function processing unit 20 uses the check message monitoring means 15E to check the abnormality of the check message from one adjacent device side. If a failure is detected according to the communication device, a failure detection notification mail including a network address unique to the communication device is generated, and mail is sent from the switch unit 10 using the field bus on the other adjacent device side where no failure is detected. Since the failure detection notification mail is sent to the server 8, these failure By confirming the network address of the detection notification mail can identify the failure occurrence location.

  Therefore, even when the switch unit 10 having the STP function is formed on the same semiconductor chip 100 as the function processing unit 20 having the existing information collecting function and control function and connected to the function processing unit 20, each communication It is possible to easily detect the occurrence of a failure in each link or each communication device of the fieldbus 5 that connects the devices in a ring connection method, and to easily identify the location of the failure. In addition, since a failure is notified using a general e-mail protocol, a failure detection function can be realized without modifying or expanding an existing communication management protocol such as STP, and it is easy for an existing system. And can be introduced at low cost.

  Conventionally, when an Ethernet switch having an STP (Spanning Tree Protocol) function is used to connect each communication device in a ring wiring system by a crossover wiring to make a network redundant, when communication is normal, By making one communication port of any Ethernet switch a blocking port (Blocking Port), an infinite loop is prevented, and when a failure occurs in any link or communication device, the blocking port is canceled by STP, A countermeasure method is adopted in which communication is maintained for a section between the failure location and the blocking port.

According to this method, it is possible to cope with the case where there is only one failure location, but if a failure occurs at a different location next time, communication cannot be maintained for the section between the two failure locations. Until the network is repaired, the operability of the entire network is reduced. For this reason, it is necessary to immediately detect the occurrence of a failure and quickly repair it in order to maintain high operability (availability) of the entire network.
According to the present embodiment, a failure detection notification mail is immediately transmitted from the communication device to the mail server in response to the occurrence of a failure, and the failure location can be specified based on the network address included in the failure detection notification mail. Therefore, the operability (availability) of the entire network can be maintained high.

In FIG. 10, the failure location is determined based on the failure detection mail from the most upstream communication device 1 in the transfer order of the check messages transmitted from the STP switch 2. By notifying the detection time, the communication device in which the failure is first detected may be specified.
In FIG. 10, the case where the check message is transmitted from the STP switch 2 to the communication apparatus 1A side has been described. However, the check message may be transmitted in the reverse direction depending on the position where the blocking port is provided. . Further, the check message may be transmitted in parallel in both directions, and the fault location can be specified more accurately.

It is a block diagram which shows the structure of the monitoring control system with which the communication apparatus concerning the 1st Embodiment of this invention is applied. It is a block diagram which shows the structure of the switch part of the communication apparatus concerning the 1st Embodiment of this invention. It is a block diagram which shows the other structure of the monitoring control system with which the communication apparatus concerning the 1st Embodiment of this invention is applied. It is a block diagram which shows the structure of the monitoring control system with which the communication apparatus concerning the 3rd Embodiment of this invention is applied. It is a block diagram which shows the structure of the switch part of the communication apparatus concerning the 3rd Embodiment of this invention. It is a block diagram which shows the detailed structure of the communication control part and function processing part of the communication apparatus concerning the 3rd Embodiment of this invention. It is a flowchart which shows the link signal monitoring process of the communication apparatus concerning the 3rd Embodiment of this invention. It is a sequence diagram which shows the link signal monitoring operation | movement of the communication apparatus concerning the 3rd Embodiment of this invention. It is a flowchart which shows the check message monitoring process of the communication apparatus concerning the 3rd Embodiment of this invention. It is a sequence diagram which shows the check message monitoring operation | movement of the communication apparatus concerning the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Communication apparatus, 2 ... STP switch, 3 ... Controller, 4 ... Central monitoring apparatus, 5 ... Field bus, 6 ... Communication line, 7 ... Upper network, 7A ... Switch, 10 ... Switch part, 11A ... Communication port A, 11B ... Communication port B, 12A ... Reception processing unit A, 12B ... Reception processing unit B, 13A ... Queue buffer A, 13B ... Queue buffer B, 14A ... Transmission processing unit A, 14B ... Transmission processing unit B, 15 ... Communication control 15A ... STP control means, 15B ... Link signal control means, 15C ... Link signal monitoring means, 15D ... Check message detection means, 15E ... Check message monitoring means, 16 ... Interrupt signal line, 16A, 16B ... Interrupt signal , 17A ... Link signal A, 17B ... Link signal B, 18 ... Data bus, 20 ... Function processor, 21 ... Internal bus, 22 ... Mail Shin means.

Claims (6)

A communication device that is connected to other devices using a ring wiring system using an Ethernet-compliant fieldbus,
Based on the Spanning Tree Protocol (STP), a switch unit that controls data communication between the function processing unit and another device via the field bus;
A function processing unit that realizes a predetermined function by exchanging various data with another device via the switch unit;
A signal processing circuit constituting the function processing unit and the switch unit includes a semiconductor chip formed as an integrated circuit. The communication device according to claim 1,
The switch unit receives two communication ports for terminating the end points of the fieldbus connected to each other in a physical layer, and a frame provided for each of the communication ports via the communication port. Two reception processing units, two queue buffers provided for each communication port and temporarily storing frames received by the reception processing unit, and provided for each communication port and stored in the other queue buffer A transmission processing unit that transmits a frame to another device via the communication port, and a frame that is stored in the queue buffer and that is addressed to the device is output to the function processing unit, and the other received from the function processing unit. A communication control unit that stores a frame addressed to the device in the queue buffer. The communication device according to claim 1,
The switch unit includes link signal monitoring means for monitoring each link signal on a physical layer periodically exchanged between two adjacent devices adjacent to the communication device via the field bus. ,
The function processing unit generates a failure detection notification mail including a network address unique to the communication device when a failure is detected by the link signal monitoring unit according to an abnormality of the link signal from one adjacent device side. A communication device comprising: a mail transmission means for transmitting the failure detection notification mail from the switch unit to an arbitrary mail server using a field bus on the other adjacent device side where the failure is not detected. The communication device according to claim 1,
The switch unit monitors a check message on a data link layer periodically transmitted so as to circulate on the field bus from a switch device that controls each communication device based on a spanning tree protocol (STP). Having message monitoring means;
The function processing unit generates a failure detection notification mail including a network address unique to the communication device when a failure is detected by the check message monitoring unit according to an abnormality of the check message from one adjacent device. A communication device comprising: a mail transmission means for transmitting the failure detection notification mail from the switch unit to an arbitrary mail server using a field bus on the other adjacent device side where the failure is not detected. A failure notification method used in a communication device connected to another device by a ring wiring method using an Ethernet-compliant fieldbus,
Based on a spanning tree protocol (STP), a data communication between the function processing unit and another device via the field bus is performed by a switch unit including a signal processing circuit formed as an integrated circuit on a semiconductor chip. Switch steps to control;
A functional processing step of realizing a predetermined function by exchanging various data with other devices via the switch unit by a functional processing unit formed of a signal processing circuit formed as an integrated circuit on the semiconductor chip; and
The switch step includes a link signal monitoring step of monitoring a link signal on a physical layer periodically exchanged between two adjacent devices adjacent to the communication device via the field bus. ,
The function processing step generates a failure detection notification mail including a network address unique to the communication device when a failure is detected in the link signal monitoring step according to an abnormality of the link signal from one adjacent device side. A failure notification method comprising: a mail transmission step of transmitting the failure detection notification mail from the switch unit to an arbitrary mail server using a field bus on the other adjacent device side where the failure is not detected. A failure notification method used in a communication device connected to another device by a ring wiring method using an Ethernet-compliant fieldbus,
Based on a spanning tree protocol (STP), a data communication between the function processing unit and another device via the field bus is performed by a switch unit including a signal processing circuit formed as an integrated circuit on a semiconductor chip. Switch steps to control;
A functional processing step of realizing a predetermined function by exchanging various data with other devices via the switch unit by a functional processing unit formed of a signal processing circuit formed as an integrated circuit on the semiconductor chip; and
The switch step is a check for monitoring a check message on a data link layer periodically transmitted to circulate on the field bus from a switch device that controls each communication device based on a spanning tree protocol (STP). A message monitoring step,
The function processing step generates a failure detection notification mail including a network address unique to the communication device when a failure is detected according to the check message abnormality from one of the neighboring devices in the check message monitoring step. A failure notification method comprising: a mail transmission step of transmitting the failure detection notification mail from the switch unit to an arbitrary mail server using a field bus on the other adjacent device side where the failure is not detected.

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